Add some spans to the Zcash codebase

src/main.cpp

@@ -4321,6 +4321,9 @@ static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned
 
 bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, const CNode* pfrom, const CBlock* pblock, bool fForceProcessing, CDiskBlockPos* dbp)
 {
+    auto span = TracingSpan("info", "main", "ProcessNewBlock");
+    auto spanGuard = span.Enter();
+
     // Preliminary checks
     auto verifier = ProofVerifier::Disabled();
     bool checked = CheckBlock(*pblock, state, chainparams, verifier);

src/net.cpp

@@ -994,6 +994,8 @@ void ThreadSocketHandler()
                 if (pnode->fDisconnect ||
                     (pnode->GetRefCount() <= 0 && pnode->vRecvMsg.empty() && pnode->nSendSize == 0 && pnode->ssSend.empty()))
                 {
+                    auto spanGuard = pnode->span.Enter();
+
                     // remove from vNodes
                     vNodes.erase(remove(vNodes.begin(), vNodes.end(), pnode), vNodes.end());
 
@@ -1152,6 +1154,8 @@ void ThreadSocketHandler()
         {
             boost::this_thread::interruption_point();
 
+            auto spanGuard = pnode->span.Enter();
+
             //
             // Receive
             //
@@ -1557,6 +1561,8 @@ void ThreadMessageHandler()
             if (pnode->fDisconnect)
                 continue;
 
+            auto spanGuard = pnode->span.Enter();
+
             // Receive messages
             {
                 TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
@@ -1890,6 +1896,7 @@ void RelayTransaction(const CTransaction& tx, const CDataStream& ss)
         if(!pnode->fRelayTxes)
             continue;
         LOCK(pnode->cs_filter);
+        auto spanGuard = pnode->span.Enter();
         if (pnode->pfilter)
         {
             if (pnode->pfilter->IsRelevantAndUpdate(tx))
@@ -2101,6 +2108,8 @@ CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNa
     nPingUsecTime = 0;
     fPingQueued = false;
     nMinPingUsecTime = std::numeric_limits<int64_t>::max();
+    span = TracingSpan("info", "net", "CNode");
+    auto spanGuard = span.Enter();
 
     {
         LOCK(cs_nLastNodeId);

src/net.h

@@ -30,6 +30,8 @@
 #include <boost/foreach.hpp>
 #include <boost/signals2/signal.hpp>
 
+#include <tracing.h>
+
 class CAddrMan;
 class CBlockIndex;
 class CScheduler;
@@ -297,6 +299,8 @@ public:
     CBloomFilter* pfilter;
     int nRefCount;
     NodeId id;
+
+    tracing::Span span;
 protected:
 
     // Denial-of-service detection/prevention